language references whatdo 2CDWIJUO2J72AEL7QTQFLPG7ZV4PCGDWYLYIH7Y


What References DoPodręcznik PHPPoprzedniRozdział 14. References ExplainedNastępnyWhat References Do PHP references allow you to make two variables to refer to the same content. Meaning, when you do: $a =& $b it means that $a and $b point to the same variable. Notatka: $a and $b are completely equal here, that's not $a is pointing to $b or vice versa, that's $a and $b pointing to the same place. The same syntax can be used with functions, that return references, and with new operator (in PHP 4.0.4 and later): $bar =& new fooclass(); $foo =& find_var ($bar); Notatka: Not using the & operator causes a copy of the object to be made. If you use $this in the class it will operate on the current instance of the class. The assignment without & will copy the instance (i.e. the object) and $this will operate on the copy, which is not always what is desired. Usually you want to have a single instance to work with, due to performance and memory consumption issues. The second thing references do is to pass variables by-reference. This is done by making a local variable in a function and a variable in the calling scope reference to the same content. Example: function foo (&$var) { $var++; } $a=5; foo ($a); will make $a to be 6. This happens because in the function foo the variable $var refers to the same content as $a. See also more detailed explanations about passing by reference. The third thing reference can do is return by reference. PoprzedniSpis treściNastępnyReferences ExplainedPoczątek rozdziałuWhat References Are Not

Wyszukiwarka

Podobne podstrony:
language references whatdo
language references spot
language references arent
language references spot
language references
language references pass
language references return
language references unset
language references
language references pass
language references return
language references unset
language references arent
C# Language Pocket Reference
VOIP Reference Guide
language expressions
Language and Skills Test Units 1 2

więcej podobnych podstron